The present invention relates to a temperature sensor which is capable of a high speed response for measuring temperature, and more particularly relates to such a temperature sensor which is particularly suitable for use in an electronic clinical thermometer.
Nowadays, for use for thermometric purposes such as clinical thermometry, electronic thermometers have been developed. Such an electronic thermometer makes use of changes in the electrical resistance of a temperature sensor which are caused by changes in the ambient temperature, and measure such electrical resistance changes by using an electronic circuit which displays a visible indication to the user indicative of the current temperature of said temperature sensor. These types of electronic thermometers have many advantages over the conventional type of mercury thermometer which makes use of the thermal expansion of liquid mercury for providing a temperature indication.
In such an electronic thermometer, the heat capacity of the temperature sensor which is brought into direct contact with the patient's body or other element of which temperature is to be sensed is an important factor which determines the time required for achieving an accurate temperature measurement. Specifically, the greater is the heat capacity of the temperature sensor, the more time is required before said temperature sensor comes to be in thermal equilibrium with the patient's body or other element of which temperature is to be sensed, and accordingly the longer a time is required before a proper temperature reading can be obtained.
Accordingly, it is desirable for the heat capacity of the temperature sensor to be reduced as much as practicable, in order to achieve as accurate temperature measurement as possible and to reduce the time required for obtaining such accurate temperature measurement. However, according to a conventional internal structure for a conventional such temperature sensor, as shown in longitudinal cross sectional view in FIG. 6 of the accompanying drawings, a metallic cap denoted by the reference numeral 52 and formed of aluminum or the like is attached to the end of a protrusion 51 of the main body casing of the thermometer, while a temperature sensitive sensor element 53 is disposed in a substantially central position within said metallic cap 52, with an adhesive filling material mass 54 such as epoxy resin is filled into said metallic cap 52 so that the protrusion 51 and the metallic cap 52 may be well and soundly bonded together by this adhesive agent mass 54 which also serves to envelop and supportingly receive the temperature sensitive sensor 53.
According to this conventional form of construction, it may occur that the temperature conduction between the metallic cap 52 and the temperature sensitive sensor 53 is unduly deteriorated by the presence of the adhesive and filling agent 54 which inevitably is introduced therebetween. Additionally, the quantity of this adhesive and filling agent 54 may become so great that the overall heat capacity of the temperature sensor may become excessively high, with the result that an excessive time is taken for attaining a stable indication of temperature, and high speed temperature measurement cannot be performed.